Indicator for engines.



W. E. JERAULD.

INDICATOR FOR ENGINES.

APPLICATION FILED DEC. a1. 1906.

908,867. Patented Jan. 5, 1909.

2 SHEETS-SHEET 1.

V W fir/ercfov "a aim Q/ m aAZZm@ J37 er'czzzoz W. E. JERAULD.

INDIGATOR FOR ENGINES.

APPLICATION FILED DEG. 31. 1906 908,867, Patented Jan. 5, 1909.

2 SHEETS-SHEET 2.

1n: NGRRIS PETERS co., wasnmawu, b. c.

UNTTED STATESPATENT OFFICE.

WILLIAM E. JERAULD, OF BOSTON, MASSACHUSETTS, ASSIGNOR TO AMERICAN STEAMGAUGE & VALVE MANUFACTURING COMPANY, OF BOSTON, MASSACHUSETTS, ACORPORATION OF NEW JERSEY.

INDICATOR FOR ENGINES.

Specification of Letters Patent.

Patented Jan. 5, 1909.

' To all whom it may concern:

Be it known that I, l VILLIAM E. JERAULD, of Boston, in the county or"Sutlolk and State of Massachusetts, have invented certain new and usefulImprovements in Indicators for Engines, of which the following is aspecification.

The present invention relates to indicators for determining the power ofsteam and other engines, and has particular reference to that class ofindicators in which the spring is held outside of the pressure cylinderof the indicator.

The object of the invention is to provide certain improvements for thistype of indicator by which the height of the pencil point may beadjusted to locate the position of the atmospheric line on the diagram,and by which the instrument may be rendered capable of securing moreaccurate results. These objects are attained by securing the springexternally to an adjustable abutment, by reducing the mass of thereciprocating parts to a minimum, and by so connecting thepencil-carrying mechanism with the piston as to cause the thrust of thelatter to be exerted along the axial line of the motion of the pistonand resistance of the spring.

Of the accompanying drawings,-Figure 1. represents a side elevation ofan indicator embodying the principles of my invention. Fig. 2 representsan elevation. as seen from the right of Fig. 1. Fig. 3 represents anaxial section of the pressure-indicating parts of the indicator. Fig. 4represents a per spect-ive view of the pencil-actuating mech anismdetached from the other parts of the apparatus.

The same reference characters indicate the same parts in all thefigures.

Referring to the drawings, 1 represents the usual drum of the indicatorupon which the card to receive the diagram is placed in the usualmanner. 2 represents the pressure cylinder having a coupling nut 3 forsecuring it detachably to a pipe tapped into the cylinder of an engine,4 represents an arm extending from the cylinder 2 and supporting thedrum, 5 represents a piston reciprocating in the cylinder 2, and 6 isthe piston-rod. These parts are all substantially the same as those usedin indicators which are now in com mon use.

The novel features of my invention consist in the construction of thepencil-operating 1 mechanism and the means for adjustably connecting theindicator spring. The latter is represented by 7 and is contained whollyoutside of the cylinder 2 so that it is protected from the effects ofthe heat in the cylinder and is used under the same conditions in whichit has previously been tested. The spring is secured at opposite ends toheads 8 and 9 which are threaded internally, and of which the former isscrewed on to the reduced lower end 10 of a screw-abutment 11. Thelatter is threaded through a yoke 12 supported by posts 13 rising fromlugs 14 on the sides of the cylinder. The lower head 9 of the spring issimilarly screwed on a threaded stud 15 connected to the piston-rod 6outside of the head 16 of the cylinder. Formed upon the yoke 12 andsurrounding the abutment 11 is a nipple 17 threaded externally andsurrounded by a threaded collar 18 which is adjustable there on. Thecollar is adapted to be retained in any adjusted position by a set-screw19, and when raised above the top of the nipple 17, acts as a stopengaged by the head 20 of the screw to limit the downward movement ofthe latter.

The marking point or pencil 21 is secured to the end of an arm 22pivoted at 23 to a link 24 pivotally supported by a lug 25 on a collar26 which is swivelly mounted upon the upper end of the cylinder 2, andis retained thereon by the head 16. The arm 22 is provided between itsends with an enlarged annular portion 27 which is adapted to surroundthe spring 7, and the opposite sides of which lie on opposite sides ofthe s ring. The sides of this annular or biiurcate portion of the armare connected by links 28 and 29 to a ring 30 by trunnions 31 ondiametrically opposite points of the latter. The pencilcarrying end ofthe arm passes through a guiding slot 32 in a post 33 rising from an arm34 which projects from the collar 26. Links 35 and 36 pivoted to the armand the post guide the marking point 21 so that it travels in a straightline parallel with the axis of the drum. The ring 30 rotatably surroundsthe end of the piston-rod 6, being su ported by a flange 37 on thelatter and he (1 in place by a projecting collar or shoul der 38 on thestud 15. The latter has aprojecting threaded end 39 detachably engagedwith the end of the piston-rod.

The sides of the slot 32 embrace the arm 22 closely and guide the samewhen the pencil point is pressed against the )aper on the drum, so thatthe latter is held firmly and Without opportunity of springing. Thiscauses a firm, well-defined mark to be made, and avoids inaccuracy. Thelinks 28 and 29 on opposite sides of the piston-rod transfer the thrustof the latter to the pencil arm in a line which is the resultant of theforces car ried through the two links, and which, therefore, coincideswith the axis of the rod. Thus thethrust is direct and axial, preventingspringing of the arm and insuring accuracy in the recording of pressureson the diagram.

It will be noted that the piston-rod terminates at the point Where it isattached to the spring, and does not continue through. the

length of the spring as in other devices of' this character, and it willalso be noted that the marking arm and the connecting links are verylight in construction. Thereby the sizes and weights of thereciprocating parts are reduced to the lowest possible terms, with aconsequent reduction in the momentum acquired by their movement, andprevention of the recording on the diagram, by reason of such momentum,of greater di'l'lerences between the extremes of pressure than actuallyexist. This removes or diminishes another source of considerable error.

In removing or applying a spring to the indicator, the screw abutment 11must be rotated to connect or release the head 8 ol' the spring. Thisrotation consequently changes the position of the abutment relative tothe yoke, but its correct location in order to position the atmosphericline, is always determined by screwing it down until its head bearsagainst the stop collar 18. Thus when the latter is set in anyparticular adjusted position, the atmospheric line may be made at thesame height on all the indicator cards, regardless of whetheror not thespring has been removed or a different spring substituted betweensuccessive employments oi the indicator.

I claim 1. In combination with the cylinder, piston, piston-rod,external spring and markeropera'ting mechanism of an indicator; a yokeexternal 01' the cylinder, an abutment threaded into said yokedetachably engaged with one end of the spring and adjustable to shiftsaid spring and the marker, thereby altering the atmospheric line onthediagram, and an adjustable stop on the yoke adapted to be placed indifferent positions and to be engaged by the abutment to limit theadjustment of said abutment.

2. In combination with the cylinder, piston, piston-rod, external springand markeroperating mechanism of an indicator; a yoke external of thecylinder having a nipple, an abutment having a head threaded throughexternal 01'' the c linder havin a ni Jule a screw abutment threadedthrough said yoke and nipple in line with the cylinder and detachablyscrewed into the head of the spring, and a collar threaded externally onsaid nipple and having a set-screw for looking it thereon; the collarlimiting the movement of the abutment toward the cylinder and serving tolocate the position of the marker.

4. In a steam-engine indicator, a cylinder, a piston therein, apiston-rod projecting through the cylinder head, a spring connectedexternally to the end of said rod, and a pencil-carrying arm bifurcatedand extending on both sides ol the spring and engaged with the rod ondiametrically opposite sides thereof.

5. In a steam-engine indicator, a cylinder, a piston therein, apiston-rod projecting throu h the cvlinder head as uin comicctedexternally to the end 01' said rod, a per cilcarrying arm havingportions extending on opposite sides of the spring and a ring rennectedby links at diametrically opposite points thereon to said arm, said ringbeing freely rotatable on the rod.

6. In a steam-engine indicator, a cylinder, a piston therein, apiston-rod projecting through. the cylinder head, a spring connectedexternally to the end of said rod, a pencilcarrying arm, a rigidabutment for the spring, the piston-rod terminating just without thecylinder head; a collar loosely mounted. on the rod linked to the pencilarm for operating the same; and a stud screwed upon the rod, having ashoulder to retain the collar and threaded to mesh with a head on thespring.

7. In a steam-engine indicator, a cylinder, a piston therein, apiston-rod projecting through the cylinder head, a spring connectedexternally to the end of said rod, a pencilcarrying arm, a post having aslot, an arm passing through said slot adapted to carry a marking pointand having a widened annular portion surrounding the spring, andconnections on opposite sides of the spring between said. arm andpiston-rod l'or oscillating the arm.

In testimony whereof I have affixed my signature, in presence of twowitnesses.

WILLIAM E. J ERAULD Witnesses:

O. F. Bnown, A. C. RATIGAN.

